Year 10 Biology & VCE Preparation - Genetics & Molecular Biology

This set of flashcards covers vocabulary and key concepts from Year 10 and VCE Biology including DNA structure, replication, protein synthesis, and genetics.

Biological Hierarchy

The structural order of genetic material from largest to smallest: Cell → Nucleus → Chromosome → DNA → Gene.

Chromosomes

Highly condensed, tightly wound structures of DNA wrapped around specialized proteins called histones.

Somatic Cells

Human body cells that contain $46$ chromosomes arranged in $23$ pairs, described as diploid ($2n$).

Autosomes

The $22$ pairs of chromosomes (totaling $44$) that determine general bodily traits rather than biological sex.

Sex Chromosomes

The $1$ pair of chromosomes determining biological sex, denoted as $XX$ for female and $XY$ for male.

Gametes

Sex cells (sperm/egg) that contain $23$ single chromosomes, described as haploid ($n$).

Karyotype

A visual map of an individual's complete set of chromosomes, paired and ordered by size and centromere position.

DNA (Deoxyribonucleic Acid)

The double-stranded helical molecule that contains all genetic blueprints for an organism.

Nucleotide

The monomer building block of DNA consisting of a Phosphate Group, Deoxyribose Sugar, and a Nitrogenous Base.

Complementary Base Pairing Rule

The rule stating that Adenine ($A$) pairs with Thymine ($T$) via $2$ Hydrogen bonds, and Cytosine ($C$) pairs with Guanine ($G$) via $3$ Hydrogen bonds.

RNA (Ribonucleic Acid)

A single-stranded molecule containing ribose sugar and the nitrogenous bases Adenine ($A$), Uracil ($U$), Cytosine ($C$), and Guanine ($G$).

DNA Replication

A process occurring during the S-phase of Interphase prior to cell division to ensure daughter cells inherit identical DNA.

DNA Helicase

The enzyme responsible for unwinding and unzipping DNA by breaking weak hydrogen bonds between complementary base pairs.

DNA Polymerase

The enzyme that adds free complementary nucleotides to template strands in the $5'$ to $3'$ direction during elongation.

DNA Ligase

The enzyme that seals the sugar-phosphate backbones of DNA strands together.

Semi-Conservative Model

The model of replication where each new DNA double helix consists of one original parent strand and one newly synthesized daughter strand.

Central Dogma of Molecular Biology

The framework describing the flow of genetic information: $DNA \rightarrow mRNA \rightarrow Protein$.

Transcription

The first stage of protein synthesis where a gene's DNA recipe is copied into a portable messenger RNA ($mRNA$) molecule in the nucleus.

RNA Polymerase

The enzyme that unzips a specific gene segment and aligns complementary RNA nucleotides against the template DNA strand.

Translation

The second stage of protein synthesis where the ribosome decodes an $mRNA$ sequence into a polypeptide chain of amino acids.

Codon

A $3$-base unit on an $mRNA$ strand that is read by the ribosome.

tRNA (Transfer RNA)

The molecule that brings specific amino acids to the ribosome, matching its anticodon with the corresponding $mRNA$ codon.

Gene

A segment of DNA that codes for a functional protein or polypeptide.

Allele

Alternative versions or variants of a specific gene, such as different eye color alleles.

Genotype

The specific genetic allele combination of an individual, represented by letters like $BB$, $Bb$, or $bb$.

Phenotype

The physical expressed characteristic of an organism resulting from its genotype and environmental interaction.

Homozygous

An individual possessing two identical alleles for a specific gene, such as $BB$ or $bb$.

Heterozygous

An individual possessing two different alleles for a specific gene, such as $Bb$.

Dominant Trait

A trait expressed in the phenotype even if only one copy of the allele is present ($B$).

Recessive Trait

A trait expressed in the phenotype only if two copies of the allele are present ($bb$).

Point Mutation

A permanent alteration in the DNA nucleotide base sequence, such as the swapping of one base for another.

Frameshift Mutation

A mutation caused by the insertion or deletion of a base, altering every downstream codon in the sequence.

Mutagens

Environmental agents that increase the rate of mutation, including UV light, radiation, and chemical toxins.